1. Field of the Invention
This invention relates to methods for purifying the air, and more specifically, to systems and methods for purifying air using ultraviolet radiation that are easily customized to accommodate different air handling systems, allow for remote location of certain components and provide superior purification levels.
2. Description of the Background
Ultraviolet (UV) germicidal irradiation has been known by scientist for over 80 years to kill fungi, bacteria, virus and other contaminants. These contaminants can pose a health hazard in buildings and other enclosed environments, and have been linked to Sick Building Syndrome and Building Related Illness, among other conditions.
A number of different systems have utilized ultraviolet radiation in order to improve air quality. Some devices are designed for use in large air handling systems while others are used to purify air on a smaller scale, such as in a single room. For example, with respect to purifying airflow in an air conditioning systems, U.S. Pat. No. 5,742,063, relates to an air sanitizer attachment which can be mounted on the top of a small air duct. The sanitizer has an aluminum housing and at least one UV emitting probe having a single ended-double tube design extending vertically downward into the duct. A light sensor allows for a determination of whether the probe is on without having to remove the device or be exposed to UV radiation. The inside of the ducts may be lined with reflective material and the entire device, including the ballast, is mounted on the top of the air duct to which it is attached.
U.S. Pat. No. 5,866,076 relates to a single-ended germicidal lamp for HVAC systems that is also mounted on the duct wall. A 110V, 60 Hz ballast is used to drive the UV tube and a mounting mechanism with a spring clamp and gaskets absorbs shock and vibration to the tube.
U.S. Pat. No. 5,817,276 relates to a method of UV distribution in an air handling system for surface and air sterilization. According to this patent, the system coil and drain pan components are subjected to UV-C radiation, to kill mold and bacteria growing on the coil and drain pan. A germicidal lamp in the form of a substantially linear germicidal tube is mounted in the air duct, with the lamp base mounted inside or on the outside of the duct and a reflector incorporated in the base.
U.S. Pat. No. 5,894,130 relates to an ultraviolet sterilization unit for use in forced air heating and cooling systems. This device is designed to insure the lamps are turned off to prevent unwanted exposure to UV radiation. The unit is mounted on a duct, such as the duct for the cool air return.
U.S. Pat. No. 5,523,057 relates to an air sterilization and filtration apparatus that can be installed in an air conditioning system. This device has an activated carbon filter and a remote power supply pack that activates the ultraviolet lights only when there is air movement in the ventilation system. A tackified first filter filters the air before it passes into a reflective chamber containing a plurality of ultraviolet lamps which then passes through an activated carbon filter. The system may be attached to the air intake chamber of a residential system or may be placed inside duct work. In addition, a post germicidal lamp may be positioned downstream of a wet coil to destroy bacteria on the wet coil.
U.S. Pat. No. 5,558,158 relates to a hygienic air handler that uses ultraviolet light downstream from the heat exchanger in a highly reflective chamber to discourage microorganisms. According to this patent, the end mounts for the UV sources are disposed inside the air handler and are fastened to the walls.
U.S. Pat. No. 5,833,740 relates to an air purifier having a turbulence generator and UV lamp tubes disposed in a reflective housing. This device is useful in the air return plenum of any system. U.S. Pat. No. 5,902,552 relates to an ultraviolet air sterilization device in which a housing and one or more mounts connect to germicidal lamps via 120V, 0.3 amp ballast. The device is mounted on the air handling duct so that the lamps protrude into the air stream of the duct.
A number of other devices have been described as being useful in either a room air application or as part of an air conditioning system. For example, U.S. Pat. No. 5,656,242 relates to an air purifier comprising a blower, porous air filters, a plurality of ballast or RF powered UV lamps disposed in a primary radiation zone and an electrostatic filter element (electrically charged grid). A reflective member/reflective walls are used to enhance irradiation in the primary irradiation zone. The purifier may be used to purify room air, or be modified for incorporation into a heating furnace.
U.S. Pat. No. 5,112,370 relates to a device for sterilizing a forced air flow using ultraviolet radiation. An elongated housing with reflecting inner surfaces accommodates an ultraviolet radiation source. A fan for drawing in and sending out air may be used or, alternately, the device may be fitted inside the output duct of an air conditioner. In the latter embodiment, three lamps are contained in a relatively short housing. The inner surface of the housing is black or dark-coated in order to absorb radiation. U.S. Pat. No. 5,837,207 relates to a portable germicidal air filter for home use incorporating an electrostatic air filter, an ultraviolet lamp and an oscillating parabolic reflector or lens for focusing the ultraviolet radiation on an upstream side of the air filter.
A number of devices are optimized to purify smaller volumes of air, such as the air in a single room. For example, U.S. Pat. No. 5,997,169 relates to a self-contained room air purification system having a first filter (comprising a particulate pre-filter, an intermediate carbon filter and an innermost HEPA filter), UV germicidal lamps and a downstream carbon mesh filter. The device is portable and can be wheeled into a room.
U.S. Pat. No. 4,017,736 relates to a portable or stationary air purification system which uses a two stage filter (consisting of a pre-filter metal mesh and a submicron laminar flow cell) in connection with a high intensity ultraviolet generator to kill microorganisms. According to this patent, a fan is used to force air through a shielded enclosure. U.S. Pat. No. 4,210,429 relates to a free-standing room air purifier that incorporates UV lamps and three separate filters (a prefilter in the inlet of the blower, a main filter element vertically stacked over the blower and lamps, and a charcoal filter disposed over the main filter element). In this device, a blower draws air into the housing and fifteen-watt germicidal lamps (General Electric part No. G15T8) are disposed inside the housing.
U.S. Pat. No. 4,786,812 relates to a portable germicidal machine which uses a plurality of ultraviolet light bulbs useful to purify room air and surfaces. The ultraviolet bulbs are disposed in a housing which has an open lower end covered with a grate. A reflective surface and fan is provided above the bulbs to draw air upward into the machine. In operation, air flows through a filter into the light chamber. Semicircular reflecting shields have holes through them to allow air flow. Bacteria on surfaces beneath the device and in air passing over the surface are killed by direct and reflected ultraviolet radiation as the device passes over the surface.
U.S. Pat. No. 4,806,768 relates to an air purifying apparatus useful in a home, office, industrial plant or hospital setting to degrade microorganisms and allergens. In this device, infrared and ultraviolet lamps are disposed in a casing having an inlet and an outlet. The infra-red light is used to heat the microorganisms to make them more susceptible to UV radiation. U.S. Pat. No. 4,931,654 relates to a radiant air sterilizing and filtering apparatus. The radiant sterilizing means (UV light source) is moveable so that it may either be enclosed in the housing or extended outward from the housing. Heating means may be provided in the housing adjacent the air inlet, and filters may be provided at the air inlet and outlet. A fan is mounted on the bottom wall to draw air into the housing. Reflectors are provided on the inner wall of the housing.
U.S. Pat. No. 5,225,167 relates to a room air sterilizer that mounts on the wall of a room and traps airborne particulate in a HEPA filter. The HEPA filter is disposed near the outflow port. A blower in the housing moves air from the intake port to the outflow port. An ultraviolet germicidal lamp disposed on the intake side of the filter destroys biocontaminants on the particulates. A prefilter may be disposed below the blower and a second UV lamp below the prefilter may be used to expose the inflow side to ultraviolet radiation. U.S. Pat. No. 5,330,722 relates to a portable air purification system using filtration and ultraviolet radiation. In this device, the filter and UV light source are moveable with respect to one another, allowing controlled irradiation of the filter surface. U.S. Pat. No. 5,453,049 relates to a corner air filtration unit designed to fit in a corner of a room, using HEPA or ULPA filters. An ultraviolet lamp may optionally be mounted in the housing.
U.S. Pat. No. 5,612,001 relates to a germicidal room air cleansing apparatus having an ellipsoid chamber formed of reflective material. UV lamps are disposed in the chamber to cleanse the air. U.S. Pat. No. 5,616,172 relates to a self-contained portable air treatment system that uses prefilters, UV lamps and a HEPA filter to purify room air.
U.S. Pat. No. 5,492,557 relates to a filter device for air purification having an electrification grid to negatively charge particles, a positively charged collector plate for attracting the negatively charged particles, and a UV lamp disposed near the collector plate to illuminate the entire length of the plate. U.S. Pat. No. 5,505,904 relates to an air disinfection unit in which air is directed past a plurality of closely spaced UV-C bulbs producing UV-C irradiation at an intensity of about 142 xcexcW/cm2.
U.S. Pat. No. 5,601,786 relates to an air purifier that uses ultraviolet radiation at two different energy intensities, i.e. ozone generating and germicidal wavelengths, to purify the air. U.S. Pat. No. 5,635,133 relates to an apparatus for killing microorganisms in a fluid medium, such as air or liquid, using filters, UV radiation and parabolic reflectors. U.S. Pat. No. 5,759,239 relates to a flat, compact air purifier which uses static electricity and metal wire gauze filters, magnetic elements and sterilizing lamps to purify the air.
A primary source of the contaminants in the circulating air comes from contaminants that accumulate on the cooling coils in the system. Efforts to eliminate these hazards has led to increased costs, particularly in commercial settings, for air handler coil cleaning. Because of the huge size and particularly the depth of cooling coils in commercial and similar settings, the cooling coil often reaches a point where it can no longer be effectively cleaned. Many coils are 12xe2x80x3 thick or more; after a period of years the center of those coils cannot be easily reached for cleaning. Further, UV units are often placed on one side of a cooling coil such that only one side can be effectively cleaned. As a result, the coils must be removed and either replaced or subjected to a chemical dip. Such procedures are time consuming and costly.
Ultraviolet devices currently used in connection with large air handling systems to eliminate contaminants are limited in their ability to efficiently and completely clean the entire coil. In addition, current devices must be custom-made for individual cooling systems. These devices are costly to design and maintain. In addition, devices that are disposed inside the duct of an air conditioning system are prone to increased wear and deterioration due to vibration and conditions inside the system.
Consequently, there is a need for an effective and durable purification system that is easily adapted for air handling systems of differing configurations, that is useful to clean both the air circulating in the system as well as the cooling elements themselves.
The present invention overcomes the problems and disadvantages associated with current strategies and designs and provides a purification apparatus that can be used to purify circulating air and also clean the cooling coils of an air conditioning system. The device is useful in both residential and commercial settings.
One embodiment of the invention is directed to apparatus for killing microorganisms in an air conditioning system. Apparatus are particularly useful for either commercial or residential systems. In a commercial setting, the apparatus may have a plurality of ballasts (e.g. 16 or more) such that the apparatus may further comprise a suppressor ballast coupled to a control relay for suppressing any electrical surge when the apparatus is activated, a plurality of fluorescent light ballasts coupled to the suppressor ballast, the fluorescent light ballasts configured to convert 60 hertz to 20-100 kilohertz, a plurality of four pin electrical connectors, wherein each of the plurality of four pin electrical connectors is coupled to one of the plurality of fluorescent light ballasts and is adapted to receive a UV-C lamp, means for de-energizing the lamps in response to a signal change, and indicator means for indicating when one or more of the plurality of lamps are energized. The four pin electrical connectors are preferably coupled to the fluorescent light ballasts via coupling means such as, for example, via wire leads from the ballast, of sufficient length that the four pin electrical connectors and UV lamps may be disposed inside an air conditioning duct, remote from the control relay, the suppressor ballast and the fluorescent light ballasts. The apparatus may further comprise a plurality of UV-C lamps designed for mating with the four pin electrical connectors and a plurality of reflectors arranged so that a reflector is disposed at at least one end of each lamp. The connectors, lamps and reflectors are preferably disposed inside the duct such that the reflectors spin as air flows through the duct. The apparatus may further comprise a safety switch, such as a xe2x85x9exe2x80x3xc3x971xc2xexe2x80x3 Edward""s brand or a high voltage push button with normally open contacts with fast make and break regardless of how pressure is applied or released having a rugged construction of phosphor bronze, self cleaning contacts that withstand shock and vibration insulated protective sleeves, locknut-type, UL recognized complete with xc2xdxe2x80x3 locknut/flexible No. 16 gauge wire leads, and 3xe2x80x3 long heavy duty shell chrome plated. At 120 volts the contact ratings are 6.0 AC amps and 3.0 DC amps. At 250 volts the contact ratings are 3.0 AC amps and 1.0 DC amps.
Another embodiment of the invention is directed to kits comprising customized air purification devices that each comprise one or more of a cover, a control relay, a safety switch, an optional suppressor ballast, a plurality of fluorescent lamp ballasts, a plurality of terminal strips, a plurality of LED indicator lights, a plurality of four pin electrical connectors, and one or more components selected from the group consisting of a plurality of UV-C lamps, a plurality of connecting wires, a plurality of multi-faceted tin reflectors, a reflective tape, a free-standing stand, a plurality of self tapping aluminum screws, a plurality of UV-C lamps, a plurality of concrete screws and a Plexiglas door.
Another embodiment of the invention is directed to methods for killing microorganisms in an air conditioning system having at least one duct for the passage of air there through, the method comprising providing connecting means for connecting to a main power source, providing a suppressor ballast coupled to the connecting means for suppressing any electrical surge when the apparatus is activated such as when 16 or more ballasts are being used, providing a fluorescent light ballast coupled to the suppressor ballast, the fluorescent light ballast configured to convert 60 hertz to 20-100 kilohertz, providing an electrical connector, coupled to the fluorescent light ballast and adapted to receive a UV-C lamp, and wherein the electrical connector is coupled to the fluorescent light ballast via coupling means such that the electrical connector may be disposed remote from the connecting means, the optional suppressor ballast and the fluorescent light ballast, providing means for de-energizing the lamp in response to a signal change, and providing indicator means for indicating when the lamp is energized.
Other embodiments and advantages of the invention are set forth in part in the description which follows, and in part, will be obvious from this description, or may be learned from the practice of the invention.